U0118high severityNetwork
Lost Communication with Alternator/Generator Module
on 2014 Ram 2500 6.7L I6 Cummins Diesel · 4WD
What this code means
Cannot communicate with the smart alternator or integrated starter-generator module.
Symptoms
- Battery warning light
- Charging system malfunction
- Battery not charging
- Voltage fluctuations
- Stop-start system disabled
Common causes
- Smart alternator failure
- CAN bus wiring to alternator
- LIN bus issue
- Alternator connector corrosion
- Voltage regulator failure
Diagnostic steps
- Check alternator fuse
- Test alternator output voltage
- Check CAN/LIN wiring to alternator
- Inspect alternator connector
- Test alternator with direct command
Repair notes
Modern smart alternators communicate on CAN or LIN bus. Check wiring and connector at alternator.
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Other Network codes on this vehicle
U0001
High Speed CAN Communication Bus
U0002
High Speed CAN Communication Bus Performance
U0003
High Speed CAN Communication Bus (+) Open
U0004
High Speed CAN Communication Bus (+) Low
U0005
High Speed CAN Communication Bus (+) High
U0006
High Speed CAN Communication Bus (-) Open
U0007
High Speed CAN Communication Bus (-) Low
U0008
High Speed CAN Communication Bus (-) High
U0009
High Speed CAN Communication Bus Shorted Together
U0010
Medium Speed CAN Communication Bus